Central Idea: An object’s motion is described by its direction and the speed.

Forces between objects can cause a change in motion. When two objects interact, each exerts a force on the other. These forces can transfer energy between objects which can cause changes in their motion.

• Moving objects have kinetic energy, which is the energy of motion.
  • The motion of an object is described by its direction and speed.
  • A change in motion is related to net force and mass.

FORCES

• The net force is the combination of all the forces acting on an object.
• Whether an object stays still or moves often depends on the effects of multiple pushes or pulls.
  • An object at rest typically has multiple forces acting on it, but they add to give zero net force on the object.
  • Forces that do not sum to zero net force can cause changes in the object’s speed or direction of motion.
• When objects collide, the energy from one object transfers to another object.
  • That transfer in energy can change an object's speed and or direction .
• Motion is described as an object’s direction and speed.
• Speed describes how fast an object is moving.
• Unless acted on by a force, objects in motion tend to stay in motion and objects at rest remain at rest.
• A force is any push or pull that causes an object to move, stop, or change speed or direction
• With objects of the same mass, the greater the force, the greater the change in motion.
  • The more massive an object, the less effect a given force will have on that object.

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FRICTION

• Friction is a force that opposes the motion of an object.